1. Field of the Invention
The present invention relates to attachment apparatus for two-wheeled vehicle parts and, more particularly, to an attachment apparatus for use in attaching bicycle parts such as a head lamp or the like to a bicycle.
2. Description of the Background Art
FIG. 23 is a side view of a head lamp for a bicycle that is attached to a handle of the bicycle by employing a conventional attachment method; and FIG. 24 is a front view showing the attachment of the bicycle head lamp of FIG. 23.
Referring to FIGS. 23 and 24, an attachment part A51 that includes an upper member 55 pivotal on a pin 11 and a lower member 57 is attached through a rubber 31 to a handle 27. An attachment part B53 attached to a lower portion of a head lamp 29 is slidably engaged with an upper portion of upper member 55.
FIG. 25 is an exploded perspective view showing the state where attachment parts A51 and B53 shown in FIGS. 23 and 24 are detached.
Referring to FIG. 25, a pair of rail members 59a and 59b are formed in the upper portion of attachment part A51. A tapped hole 13 is formed between rail members 59a and 59b. A recess 63 is formed in a portion in an opposite direction from the direction of tapped hole 13 between rail members 59a and 59b. Attachment part A51 is formed of upper member 55 and lower member 57, which are both pivotal on pin 11. This allows attachment part A51 to be attached to tubular component parts of the bicycle such as a handle or the like.
Grooves 60a and 60b that are slidable with respect to rail members 59a and 59b of attachment part A51 are formed in a lower portion of attachment part B53. A flat engagement piece 61 partially projected from attachment part A51 is formed between grooves 60a and 60b. An attachment hole 23 is an aperture provided for attaching attachment part B53 to head lamp 29 by employing a screw or the like.
FIG. 26 is a view showing the state where grooves 60a and 60b of attachment part B53 in the conventional example are sliding while fitting on rail members 59a and 59b of attachment part A51.
Referring to FIG. 26, engagement piece 61 that is made of, e.g., plastic resin and attached to the lower portion of attachment part A51 has a projection 65 formed in its lower portion. Projection 65 is in the form of being engaged with recess 63. As shown in FIG. 26, when attachment part B53 moves in an "A" direction, a spheroidal portion of a tip end of engagement piece 61 first makes contact with a protrusion 64 of upper member 55 of attachment part A51. Since engagement piece 61 is formed of plastic resin, engagement piece 61 deforms to deflect upward so that engagement piece 61 may avoid a collision caused by the contact with protrusion 64. Then, engagement piece 61 deforms further upward by contacts between projection 65 and protrusion 64.
FIG. 27 is a cross-sectional view showing the state where attachment parts A51 and B53 are completely engaged with each other from the state shown in FIG. 26.
Referring to FIG. 27, projection 65 on engagement piece 61 is engaged with recess 63 formed in upper member 55 when going completely beyond protrusion 64. This engagement between projection 65 and recess 63 prevents disengagement of attachment part B53 even if a force is applied in a direction in which attachment part B53 is disengaged, i.e., a "B" direction.
A sufficient attachment strength is not provided in the above-described conventional attachment apparatus for bicycle parts. With reference to FIG. 27, attachment part B53 is not detached from attachment part A51 due to the engagement between projection 65 and recess 63 in the stage that a small force is applied in the "B" direction. However, as shown in FIG. 26, engagement piece 61 has an elastic state such as of plastic resin. Thus, when a force larger than a predetermined force is applied in the "B" direction, engagement piece 61 is liable to be deformed in such form as shown in FIG. 26 by the applied force, thereby releasing the engagement. As described above, there is no sufficient reliability in the engagement between attachment parts A51 and B53. Particularly, no sufficient attachment strength is provided in view of vibration applied by the use of bicycles or the like.